The doctor who performed the work has violated his oath to do no harm.
Any rational person on the street can easily tell that this guy is mentally ill. So yes, as you said, how much more should a doctor be able to tell that they are dealing with a sick mind. But instead of stopping him, and getting him the help he needs, instead they enable his delusions.
They take the money and do it anyway. There is no doctor who looked at this guy when they finished mutilating him and said to themselves, 'Yes! I did something good today.'
The doctors have to know that they are turning him into a monstrous freak. I guess they just don't care. As long check clears, apparently they will do anything.